Exploiting the capabilities of modern GPUs for dense matrix computations

We present several algorithms to compute the solution of a linear system of equations on a graphics processor (GPU), as well as general techniques to improve their performance, such as padding and hybrid GPU‐CPU computation. We compare single and double precision performance of a modern GPU with unified architecture, and show how iterative refinement with mixed precision can be used to regain full accuracy in the solution of linear systems, exploiting the potential of the processor for single precision arithmetic. Experimental results on a GTX280 using CUBLAS 2.0, the implementation of BLAS for NVIDIA^® GPUs with unified architecture, illustrate the performance of the different algorithms and techniques proposed. Copyright © 2009 John Wiley & Sons, Ltd.     

Interaction Nets with McCarthy's amb

Interaction nets are graphical rewrite systems which have been successfully used to implement various efficient evaluation strategies in the λ-calculus (including optimal reduction). However, they are intrinsically deterministic and this prevents from applying these techniques to concurrent languages where non-determinism plays a key rôle. In this paper we show that a minimal extension —the addition of one agent in the spirit of McCarthy's amb operator —allows us to define non-deterministic processes such as angelic and infinity merge, and more generally, to encode process calculi and wide classes of term rewriting systems (including systems defining parallel functions). We also show that Alexiev's INMPP (interaction nets with multiple principal ports) can be encoded, for which we give a textual calculus and a type system that ensures the absence of deadlock.     

Hydrodynamic conditions induce changes in secretion level and glycosylation patterns of Von Willebrand factor (vWF) in endothelial cells

The effect of low-speed agitation on the level of secretion and glycosylation patterns of the Von Willebrand factor in endothelial cells cultured in 6-cm Petri dishes located in a rotating platform was studied. In this simple system, complex and non-intuitive velocity fields arise. As revealed by simple calculations of tangential velocities and CFD analysis, flow behavior strongly varies as a function of radial distance and rotational velocity. We found significant differences in both secretion level and glycosylation extent and completeness, as a result of relatively small changes in rotational speed. Results obtained support the hypothesis that differences in hydrodynamic conditions may induce important changes in the secretion and assembly of glycoproteins in mammalian cell cultures.     

Unripe banana flour as an ingredient to increase the undigestible carbohydrates of pasta

Banana is a starchy food that contains a high proportion of undigestible compounds, such as resistant starch and non-starch polysaccharides. There is an excess of production and large quantities of bananas are lost. The objective of this study was to use unripe banana flour as a food ingredient to make pasta (spaghetti) of high quality, on the basis of low-carbohydrate digestibility, and increased resistant starch and antioxidant phenolics contents.     

Prevalence of Salmonella on retail broiler chicken meat carcasses in Colombia

A cross-sectional study was performed to estimate the prevalence of Salmonella on retail market chicken carcasses in Colombia. A total of 1,003 broiler chicken carcasses from 23 departments (one city per department) were collected via a stratified sampling method. Carcass rinses were tested for the presence of Salmonella by conventional culture methods. Salmonella strains were isolated from 27 % of the carcasses sampled. Logistic regression analysis was used to determine potential risk factors for Salmonella contamination associated with the chicken production system (conventional versus free-range), storage condition (chilled versus frozen), retail store type (supermarket, independent, and wet market), poultry company (integrated company versus nonintegrated company), and socioeconomic stratum. Chickens from a nonintegrated poultry company were associated with a significantly (P < 0.05) greater risk of Salmonella contamination (odds ratio, 2.0) than were chickens from an integrated company. Chilled chickens had a significantly (P < 0.05) higher risk of Salmonella contamination (odds ratio, 4.3) than did frozen chicken carcasses.     

Interaction of the human intestinal microbiota with the release of bound phenolic compounds in chickpea (Cicer arietinum L.)

The objective of this work was to release bound phenolic compounds (PC) from chickpea by the interaction of the microbiota of a volunteer and to identify the enzymes implied to deliver these PC. The highest amount of PC was released at 12 and 24 h (16.8–18.5 mg GAE/g). Higher antioxidant capacity was observed in these hours through 2,20-azino-bis-(3ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power and 2,´2.Azobis (2 methylpropionamidine) techniques. Escherichia, Klebsiella, Bacteroides and Veillonella were some genera identified in the microbiota implied in delivered PC. The principal PC identified by ultra performance liquid chromatography–mass spectrometry were flavonoids. Proteomic analysis identified hundreds of proteins from the intestinal microbiota after 12 h of fermentation, including enzymes related to the release of bound PC from chickpea such as pectin esterase. Therefore, this enzyme could be used in other food sources for the release of PC bound to the food matrix and thus take advantage of their bioactive benefits.     

Minimal processing of a Granny Smith apple purée by microwave heating

Consumers are demanding more “fresh appearing”, more convenient and healthier fruit products. At the same time fruit industries look for technologies to decontaminate fruit products by minimising losses of nutritional and sensorial quality. Microwave heating technology gives the opportunity to have a fast heat process in a continuous mode. Granny Smith apple purée, with natural additives, was prepared and submitted to a) short microwave treatment during 35 s at 652 W. The effects of the treatment were evaluated looking for, the stability of vitamin C, total polyphenol content, as well as viscosity, colour and titratable acidity over a period of two weeks. Its effect on E. coli, L. innocua and indigenous microbiota was evaluated. Results showed that while a reduction of microorganisms was achieved, the treatment could not inactivate the enzymes present in the product and prevent vitamin C degradation. On the other hand the treatment did not affect the stability of the viscosity and titratable acidity during storage period.

Industrial relevance

A minimal industrial process of apple products that reduces pathogenic microorganisms, while maintaining nutritional and sensorial attributes is needed to increase the competitiveness of the fruit sector. Short microwave treatment may be a solution to achieve this objective.